1. Field of the Invention
The present invention generally relates to medical devices, methods, and systems. More specifically, the present invention provides techniques for selectively heating and shrinking tissues, particularly for the noninvasive treatment of urinary incontinence and hernias, for cosmetic surgery, and the like.
Urinary incontinence arises in both women and men with varying degrees of severity, and from different causes. In men, the condition occurs most often as a result of prostatectomies which result in mechanical damage to the sphincter. In women, the condition typically arises after pregnancy where musculoskeletal damage has occurred as a result of inelastic stretching of the structures which support the genitourinary tract. Specifically, pregnancy can result in inelastic stretching of the pelvic floor, the external sphincter, and most often, to the tissue structures which support the bladder and bladder neck region. In each of these cases, urinary leakage typically occurs when a patient""s intra-abdominal pressure increases as a result of stress, e.g. coughing, sneezing, laughing, exercise, or the like.
Treatment of urinary incontinence can take a variety of forms. Most simply, the patient can wear absorptive devices or clothing, which is often sufficient for minor leakage events. Alternatively or additionally, patients may undertake exercises intended to strengthen the muscles in the pelvic region, or may attempt behavior modification intended to reduce the incidence of urinary leakage.
In cases where such non-interventional approaches are inadequate or unacceptable, the patient may undergo surgery to correct the problem. A variety of procedures have been developed to correct urinary incontinence in women. Several of these procedures are specifically intended to support the bladder neck region. For example, sutures, straps, or other artificial structures are often looped around the bladder neck and affixed to the pelvis, the endopelvic fascia, the ligaments which support the bladder, or the like. Other procedures involve surgical injections of bulking agents, inflatable balloons, or other elements to mechanically support the bladder neck.
Each of these procedures has associated shortcomings. Surgical operations which involve suturing of the tissue structures supporting the urethra or bladder neck region require great skill and care to achieve the proper level of artificial support. In other words, it is necessary to occlude or support the tissues sufficiently to inhibit urinary leakage, but not so much that intentional voiding is made difficult or impossible. Balloons and other bulking agents which have been inserted can migrate or be absorbed by the body. The presence of such inserts can also be a source of urinary tract infections. Therefore, it would be desirable to provide an improved therapy for urinary incontinence.
A variety of other problems can arise when the support tissues of the body have excessive length. Excessive length of the pelvic support tissues (particularly the ligaments and fascia of the pelvic area) can lead to a variety of ailments including, for example, cystocele, in which a portion of the bladder protrudes into the vagina. Excessive length of the tissues supporting the breast may cause the breasts to sag. Many hernias are the result of a strained, torn, and/or distended containing tissue, which allows some other tissue or organ to protrude beyond its contained position. Cosmetic surgeries are also often performed to decrease the length of support tissues. For example, abdominoplasty (often called a xe2x80x9ctummy tuckxe2x80x9d) is often performed to decrease the circumference of the abdominal wall. The distortion of these support tissues may be due to strain, advanced age, congenital predisposition, or the like.
Unfortunately, many support tissues are difficult to access, and their tough, fibrous nature can complicate their repair. As a result, the therapies now used to improve or enhance the support provided by the ligaments and fascia of the body often involve quite invasive surgical procedures.
For these reasons, it would be desirable to provide improved devices, methods, and systems for treating fascia, tendons, and the other support tissues of the body. It would be particularly desirable to provide improved noninvasive or minimally invasive therapies for these support tissues, especially for the treatment of urinary incontinence in men and women. It would further be desirable to provide treatment methods which made use of the existing support structures of the body, rather than depending on the specific length of an artificial support structure.
2. Description of the Background Art
U.S. Pat. No. 5,423,811 describes a method for RF ablation using a cooled electrode. U.S. Pat. Nos. 5,458,596 and 5,569,242 describe methods and an apparatus for controlled contraction of soft tissue. An RF apparatus for controlled depth ablation of soft tissue is described in U.S. Pat. No. 5,514,130.
U.S. Pat. No. 4,679,561 describes an implantable apparatus for localized heating of tissue, while U.S. Pat. No. 4,765,331 describes an electrosurgical device with a treatment arc of less than 360 degrees. An impedance and temperature generator control is described in U.S. Pat. No. 5,496,312. Bipolar surgical devices are described in U.S. Pat. Nos. 5,282,799, 5,201,732, and 728,883.
The present invention provides devices, methods, and systems for shrinking of collagenated tissues, particularly for treating urinary incontinence in a noninvasive manner. In contrast to prior art techniques, the present invention does not rely on implantation of balloons or other materials, nor does it rely on suturing, cutting, or other direct surgical modifications to the natural support tissues of the body. Instead, the present invention directs energy to a patient""s own support tissues. This energy heats fascia and other collagenated support tissues, causing them to contract without substantial necrosis of adjacent tissues. The energy will preferably be applied through a large, cooled electrode having a substantially flat electrode surface. Such a cooled plate electrode is capable of directing electrical energy through an intermediate tissue and into fascia, while the cooled electrode surface prevents injury to the intermediate tissue. Ideally, the plate electrode comprises an electrode array which includes several discrete electrode surface segments so that the current flux can be varied to selectively target and evenly heat the fascia. In some embodiments, the tissue is heated between a pair of parallel cooled electrode surfaces, the parallel surfaces optionally being planar, cylindrical, spherical, or the like. Alternatively, the tissue may be treated with a bipolar probe, particularly after pre-cooling the intermediate tissue to selectively vary tissue impedance and thereby direct the heating current through the target tissue.
In a first aspect, the present invention provides a probe for therapeutically heating a target tissue of a patient body through an intermediate tissue. The probe comprises an electrode with an electrode surface which is engageable against the intermediate tissue. The electrode surface is substantially flat, and a cooling system is coupled to the electrode. The cooling system allows the electrode surface to cool the engaged intermediate tissue while an electrical current flux from the electrode surface therapeutically heats the target tissue.
The electrode surface will generally be sufficiently flat to direct the current flux through the cooled intermediate tissue and into the target tissue while the cooling system maintains the intermediate tissue at or below a maximum safe tissue temperature. To direct the current flux, heating may be provided between a pair of electrode surfaces, the electrode surfaces typically being separated by a distance from about ⅓ to about 5.0 times the least width of the electrodes, preferably being separated by a distance from about xc2xd to about 2.0 times the least electrode width. In many embodiments, a temperature sensor will monitor the temperature of the target tissue or the intermediate tissue. A control system will often selectively energize the electrode and/or cooling system in response to the monitored temperature.
In another aspect, the present invention provides a probe for applying energy to fascia from within the vagina of a patient body. The fascia is separated from the vagina by a vaginal wall. The probe comprises a probe body having a proximal end and a distal end, the probe having a length and a cross-section selected to permit introduction into the vagina. An energy transmitting element is mounted to the probe body. The transmitting element is capable of transmitting sufficient heating energy through the vaginal wall to heat and contract the fascia. A cooling system is disposed adjacent to the transmitting element. The cooling system is capable of maintaining the vaginal wall adjacent the probe below a maximum safe temperature when the fascia is heated by the transmitting element.
The present invention also provides a method for shrinking a target collagenated tissue within a patient body through an intermediate tissue. The method comprises directing energy from a probe, through the intermediate tissue, and into the target tissue. The energy heats the target tissue so that the target tissue contracts. The intermediate tissue is cooled with the probe to avoid injuring the intermediate tissue when the target tissue is heated by the probe.
In yet another aspect, the present invention provides a method for directing energy into a target tissue of a patient body through an intermediate tissue. The method comprises electrically coupling a first electrode to the patient body. A second electrode is electrically coupled to the intermediate tissue, the second electrode being mounted on a probe. The intermediate tissue is cooled by the probe, and an electrical potential is applied between the first and second electrodes. An electrode surface of the second electrode is sufficiently large and flat to provide a current flux that extends through the cooled intermediate tissue so that the current flux heats the target tissue.
In yet another aspect, the present invention provides a method for therapeutically heating a target zone of a tissue within a patient body. The method comprises engaging a tissue adjacent to the target zone with a probe. The adjacent tissue is pre-cooled with the probe, and the target zone is heated by directing energy from the probe, through the pre-cooled adjacent tissue, and into the target zone.
In another aspect, the present invention provides a kit for shrinking a target collagenated tissue within a patient body through an intermediate tissue. The kit comprises a probe having an energy transmitting element adapted to direct an energy flux through the intermediate tissue and into the target tissue. A cooling system is adjacent to the transmitting element to cool the intermediate tissue. The kit also includes instructions for operating the probe. The instructions comprise the steps of directing energy from the energy transmitting element of the probe, through the intermediate tissue, and into the target tissue so as to heat and shrink the target tissue. The intermediate tissue is cooled with the cooling system of the probe to avoid injuring the intermediate tissue.
In a further aspect, the present invention further provides a method for teaching. The method comprises demonstrating cooling of a surface with a probe. Directing of energy from the probe is also demonstrated, the energy being directed through the surface and into the underlying structure to effect shrinkage of the structure.
In yet another aspect, the present invention provides a system for therapeutically heating a target zone within a tissue. The system comprises a first electrode having a first electrode surface which is engageable against the tissue. A second electrode has a second electrode surface which can be aligned substantially parallel to the first electrode surface, with the tissue positioned therebetween. An electrical current flux between these parallel electrodes can substantially evenly heat the target zone. A cooling system is coupled to at least one of the electrodes for cooling the electrode surface. Generally, radiofrequency current is used to avoid tissue stimulation.
In another aspect, the present invention provides a method for therapeutically heating a target zone of a patient body. The target zone is disposed within a tissue between first and second tissue surfaces. The method comprises engaging a first electrode surface against the first tissue surface. A second electrode surface is aligned substantially parallel with the first electrode surface and against the second tissue surface. An electrical potential is applied between the first and second electrodes so as to produce an electrical current flux which heats the target zone. At least one of the first and second tissue surfaces is cooled by the engaged electrode.
The present invention also provides a probe for heating a target tissue of a patient body through an intermediate tissue. The probe comprises a probe body supporting an electrode array. The electrode array includes a plurality of electrode surface segments. The electrode surface segments are simultaneously engageable against the intermediate tissue, and a cooling system is coupled to the probe for cooling the electrode surface segments. A control system is also coupled to the electrode surface segments. The control system is adapted to selectively energize the electrode surface segments so as to heat the target tissue to a treatment temperature while the cooling system maintains the intermediate tissue (which is disposed between the electrode array and the target zone) at or below a maximum safe tissue temperature.
In another aspect, the present invention provides a method for therapeutically heating a target zone of a tissue within a patient body. The method comprises engaging a probe against the tissue. The probe has a plurality of electrode surface segments, and the tissue is cooled adjacent the probe by the electrode surface segments. An electrical current flux is directed from the electrode surface segments, through the cooled tissue, and into the target zone by selectively energizing the electrode surface segments so that the current flux substantially evenly heats the target zone.
In some embodiments of the present invention, tissue contraction energy will preferably be in the form of a radiofrequency (RF) electrical current applied through an electrolytic solution. Often times, the electrolytic solution will be introduced into the patient""s bladder through a transurethral probe, and will provide electrical coupling between an electrode of the probe and the bladder wall. To enhance control over the therapeutic heating and shrinking of tissues applied internally through an electrolytic solution, a controlled volume of both the electrolytic solution and an electrically and thermally insulating gas can be introduced into the patient""s bladder (or some other hollow body organ). By orienting the patient so that the electrically conductive solution is positioned within the bladder adjacent the pelvic support tissues, the conductive solution can transmit electrical current over a relatively large and fairly well controlled interface between the conductive solution and the bladder wall, while the gas prevents transmission of the RF energy to the delicate abdominal tissues above the bladder. The electrically conductive solution may also provide direct cooling of the bladder wall before, during, and/or after the therapeutically heating RF energy is transmitted. Such cooling may be enhanced by circulating chilled conductive solution through the bladder, optimizing the electrical properties of the solution to minimize heat generated within the solution, and the like. In the exemplary embodiment, the RF energy is transmitted between the electrolyte/bladder wall interface and a cooled, substantially flat electrode of a vaginal probe so as to shrink the endopelvic fascia therebetween and thereby inhibit incontinence.
In this aspect of the present invention, a method for heating a target tissue within a patient body heats tissue separated from a body cavity by an intermediate tissue. The method comprises introducing a conductive fluid into the cavity. An electrical current is passed from the conductive fluid, through the intermediate tissue, and into the target tissue to effect heating of the target tissue. The intermediate tissue is cooled by the conductive fluid. The conductive fluid will generally comprise an electrolytic solution such as saline, and the saline will preferably be chilled. Advantageously, by directing RF current between such a chilled electrolytic solution and a large cooled plate electrode, an intermediate collagenated tissue therebetween can be selectively raised above about 60xc2x0 C., thereby inducing shrinkage. The tissue which is engaged directly by the cooled electrode and chilled electrolytic solution (on either side of the collagenated tissue) is preferably maintained below a maximum safe temperature of about 45xc2x0 C.
In another aspect, the invention provides a method for shrinking a target tissue within a patient body. The target tissue is separated from a body cavity by an intermediate tissue. The method comprises introducing a conductive fluid and an insulating fluid into the cavity. These fluids are positioned within the cavity by orienting the patient. The conductive and insulating fluids will have differing densities, and the patient will be oriented so that the conductive fluid is disposed adjacent the target tissue, while the insulating fluid is disposed away from the target tissue. The target tissue can then be heated by passing an electrical current from the conductive fluid, through the intermediate tissue, and into the target tissue. The intermediate tissue can also be cooled by the conductive fluid. The conductive fluid will often comprise an electrolytic liquid such as saline, while the insulating fluid will typically comprise a gas such as air, carbon dioxide, or the like. By carefully controlling the volumes of these fluids within the body cavity, and by properly orienting the patient, gravity and the differing electrical properties of these contained fluids can be used to selectively transfer RF current from an electrode to a relatively large, controlled surface area of the body cavity without requiring the introduction of a large or mechanically complex electrode structure.
In another aspect, the present invention provides a method for treating urinary incontinence. The method comprises introducing a fluid into the bladder, and transmitting electrical current from the fluid, through the bladder wall, and into a pelvic support tissue so that the current heats and shrinks the pelvic support tissue and inhibits urinary incontinence. The bladder wall is cooled with the conductive fluid.
In another aspect, the present invention provides a system for shrinking a pelvic support tissue of a patient body. The pelvic support tissue is separated from a urinary bladder by a bladder wall. The system comprises a first probe having a proximal end and a distal end adapted for transurethral insertion into the bladder. A first electrode is disposed near the distal end, as is a fluid in-flow port. A sealing member is proximal of the in-flow port for sealing a conductive fluid within the bladder such that the first electrode is electrically coupled to the bladder wall by the conductive fluid. A second electrode is adapted for transmitting current to a tissue surface of the patient body without heating the tissue surface. A power source is coupled to the first and second electrodes to heat and shrink the pelvic support tissue. In many embodiments, the second electrode will comprise a cooled plate electrode of a vaginal probe, so that the endopelvic fascia can be selectively heated between the vagina and the conductive fluid within the bladder.
In another aspect, the present invention provides a system for shrinking a pelvic support tissue of a patient body. The pelvic support tissue is separated from a urinary bladder by a bladder wall. The system comprises a first probe having a proximal end, a distal end adapted for transurethral insertion into the bladder, and a first electrode near the distal end. A second probe has a proximal end, a distal end adapted for insertion into the vagina, and a second electrode near the distal end. A power source is coupled to the first and second electrodes to heat and shrink the pelvic support tissue. Generally, the first probe will also include a tordial balloon or other member for sealing around the circumference of the probe, thereby allowing saline or some other conductive fluid to be captured within the bladder. In some embodiments, in-flow and out-flow ports distal of the balloon may allow circulation of chilled saline or the like, enhancing the direct cooling of the bladder wall. One or more gas ports may also be provided distal of the balloon for introducing and/or controlling a volume of air, CO2 or some other insulating gas, or such gasses may alternatively pass through the conductive fluid ports. By carefully controlling the volumes of air and saline within the bladder, and by orienting the patient so that the saline is only in contact with the bladder wall adjacent the endopelvic fascia, such a structure can provide both selective electrical conduction and cooling over a large, controlled surface of the bladder wall with very little mechanical complexity or trauma.
In general, the tissue contraction energy of the present invention can be applied as intermittent pulses of radiofrequency (RF) electrical current transmitted between cooled electrodes. The electrodes will ideally be large, relatively flat plates having rounded edges, but may alternatively comprise a curved conductive surface of an inflatable balloon, or the like. These electrodes will preferably be oriented toward each other, and will generally be actively cooled while the electrodes are energized by a RF potential, and between RF pulses. Cooling will preferably also be provided both before and after the heating cycles, and needle mounted temperature sensors will ideally provide direct feedback of the tissue temperature so that selected treatment zone is heated to about 60xc2x0 C. or more, while heating of the tissues adjacent the electrodes is limited to about 45xc2x0 C. or less.
In one aspect, the present invention provides a method for heating and/or shrinking a target tissue within a patient body. The target tissue is separated from a tissue surface by an intermediate tissue. The method comprises coupling an electrode of a probe to the tissue surface and cooling the intermediate tissue with the probe. The electrode is intermittently energized to heat, and preferably to shrink, the target tissue through the cooled intermediate tissue. Typically, current is driven through the electrode for between about 10 and 50% of a heating session. For example, the electrode may be energized for 15 secs. and turned off for 15 secs. repeatedly during a heating session so that current is driven from the electrode for about 50% of the duty cycle.
In another aspect, the invention provides a system for shrinking a target tissue of a patient body. The system comprises a probe having a first electrode for electrically coupling the probe to the tissue surface. A second electrode can be coupled to the patient body, and a controller is coupled to the first and second electrodes. The controller is adapted to intermittently energize the electrodes with an RF current so that the electrodes heat and shrink the target tissue, often while minimizing collateral damage to tissues surrounding the target tissue. In many embodiments, The target tissue is separated from a tissue surface by an intermediate tissue. A cooling system may be disposed adjacent the electrode, so that the cooling system can maintain the intermediate tissue below a maximum safe temperature. Generally, the cooling system will cool both the first electrode and the intermediate tissue engaged by the electrode surface.
As described above, the energy to heat and selectively shrink the target collagenated support tissues will preferably be applied by conducting radiofrequency (RF) electrical current through tissue disposed between large, cooled plate electrodes. These electrodes will preferably be sufficiently parallel to each other and in alignment so as to direct the current flux evenly throughout a target region of the target tissue. To maintain this alignment, the electrodes will generally be mechanically coupled to each other, ideally using a clamp structure which allows the target tissue to be compressed between the electrode surfaces. Compressing the tissues can enhance the uniformity of the heating, particularly when the tissue is compressed between the electrode surfaces so that the surfaces are separated by less than their widths. Cooling of the electrodes can limit heating of tissues adjacent the electrode surfaces to about 45xc2x0 C. or less, even when the treatment zone between the electrodes is heated to about 60xc2x0 C. or more so as to effect shrinkage.
In this aspect, the present invention provides a device for therapeutically heating tissue. The device comprises a first electrode having an electrode surface. A cooling system is thermally coupled to the first electrode. A second electrode is mechanically coupled to the first electrode. The second electrode has an electrode surface oriented toward the first electrode surface.
Generally, a clamp structure couples the electrodes and allows the tissues to be compressed between parallel electrode surfaces. The clamp structure will often be adapted to maintain the electrode surfaces in alignment to each other, and also to maintain the electrode surfaces sufficiently parallel so as to direct an even electrical current flux through a target region of the clamped tissue. At least one of the electrodes will preferably be mounted on a probe adapted for insertion into a patient body. The probe will ideally be adapted for noninvasive insertion into a body cavity through a body orifice. The clamp structure will preferably vary a separation distance between electrodes mounted on two such probes, and a temperature sensor will ideally be extendable into the target tissue to provide feedback on the heating process. The temperature sensor can be mounted on a needle which is retractably extendable from adjacent one of the electrodes toward the other, or the needle may protrude permanently so as to extend into the target tissue as the electrode surfaces are clamped together.
In another aspect, the present invention provides a method for selectively shrinking a target tissue. The method comprises clamping a target tissue between a plurality of electrode surfaces. The clamped target tissue is heated by transmitting a current flux between the electrode surfaces. At least one of the electrode surfaces is cooled to limit heating of intermediate tissue disposed between the at least one electrode and the target tissue.
According to another aspect of the invention, the energy can be in the form of focused ultrasound energy. Such ultrasound energy may be safely transmitted through an intermediate tissue at lower power densities so as to avoid and/or minimize collateral damage. By focusing the ultrasound energy at a target region which is smaller in cross section than the ultrasound energy transmitter, the power densities at the target region will be sufficiently high to increase the temperature of the target tissue. Preferably, the target tissue will be raised to a temperature of about 60xc2x0 C. or more, while the intermediate tissue remains at or below a maximum safe temperature of about 45xc2x0 C. A cooling system may actively cool the intermediate tissue.
Targeting flexibility is enhanced by using a phased array ultrasound transmitter. Such phased array transmitters will be particularly beneficial for selectively shrinking fascia, ligaments, and other thin support tissues of the body, particularly where those tissues are disposed roughly parallel to an accessible tissue surface. Focused ultrasound energy is particularly well suited for heating and shrinking the pelvic support tissues from a vaginal probe.
In this aspect, the present invention provides a method for heating a target tissue within a patient body. The target tissue is separated from a tissue surface by an intermediate tissue. The method comprises acoustically coupling an ultrasound transmitter to the tissue surface. The ultrasound energy is focused from the transmitter, through the intermediate tissue, and onto the target tissue so that the target tissue is therapeutically heated. Preferably, the focused ultrasound energy heats and shrinks a collagenated tissue. In the exemplary embodiment of the present method, the ultrasound transmitter is inserted into a vagina of the patient body to shrink an endopelvic support tissue so that incontinence is inhibited.
In another aspect, the present invention provides a system for heating a target tissue. The system comprises a probe having an ultrasound transmitter for focusing ultrasound energy through the intermediate tissue so as to heat the target tissue. Preferably, a temperature sensor is coupled to the probe and exposed to at least one of the intermediate tissue and the target tissue for sensing a tissue temperature. In many embodiments, a controller is coupled to the probe. The controller will generally be adapted to direct the ultrasound energy from the transmitter into the target tissue so as to heat the target tissue to about 60xc2x0 C. or more. The controller will typically limit a temperature of the intermediate tissue to about 45xc2x0 C. or less.
In yet another aspect, the present invention provides a method for selectively heating a predetermined target tissue. The target tissue is disposed adjacent another tissue, and the method comprises generating a temperature differential between the adjacent tissue and the target tissue. The target tissue is heated by conducting a heating electrical current into the target tissue after generating the temperature differential. The heating current is conducted so that the temperature differential urges the heating current from the adjacent tissue into the target tissue.
In a related aspect, the invention provides a system for selectively heating a predetermined target tissue. The target tissue is disposed adjacent another tissue, and the system comprises a probe having a surface oriented for engaging a tissue surface. A pre-cooler or a pre-heater is coupled to the probe surface so as to produce a temperature differential between the target tissue and the adjacent tissue. At least one tissue-heating electrode is couplable to the target tissue to conduct an electrical current into the tissues. The heating electrode defines a nominal current distribution when the current is conducted into the tissues and the tissues are at a uniform body temperature. The heating electrode produces a tailored current distribution when the current is conducted into the tissues and the tissues exhibit the temperature differential. The tailored current distribution results in less collateral damage to the adjacent tissue than the nominal current distribution when the target tissue is heated by the current to a treatment temperature.
In a final aspect, the invention provides a probe for selectively heating a target tissue. The target tissue is separated from a tissue surface by an intermediate tissue. The probe comprises a surface oriented for engaging the tissue surface. A pair of bi-polar electrodes are disposed along the probe surface. A cooling system is thermally coupled to the electrodes and to the probe surface, adjacent the electrodes, so as to cool the intermediate tissue.